Hand operated



Dec. 144, 1937. 13. s. 1'. v.BISHOP Er AL Re- 20579 yHAND OPERATED, ELEHJ'VIRI)` CONTROLLED, TAI-PING DEVICE original Filed March 16; 1934 Dec. 14,

B. S. T. BISHOP ET AL HAND OPERATED, ELECTRIC' CONTROLLED, TAPPING DEVICE original Filed March l, .1954 3 shei-.s--shem4 2 Dec.- 14, 1937. B. s. r. BISHOP ET AL Re- 20,579 HAND OPERTED, ELECTRIC CONTROLLED, TAPPING DEVCE Original Filed March 16, 1954 I 5 Sheets-Sheet 3 I Ja/ezra/Z Reissues Dee. 14, 1937 AUNi'l'ED STATES PATENT OFFICE i;

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Benjamins. '.r. Bishop, Shrewsbury, and Percival E. DowfLeicester, Mass., assignors to Leland- Giiord (Qonlllany,- a corporation of Massacllllsetta original No. 1,970,218; lated Anm: v14, v192.4, se. rial nannesz, Maren 1s, 1934. Application for reissue aufm lz, 193s, serial Nn. 95,693

-ss-clalnis. (el. lil-13s) This invention relates to tappind machines.

Tapping machines, prior to this invention, have 'Y usually had clutches, reversing mechanism and the like to change the direction of rotation of the tap for advancing it into and for retractlngit o ut' of the work, the direction of rotation of the source of power for rotating the tap usually being constant. v

It is an object of this invention to provide a tapping machine so arranged that the direction of rotation of the source of power, usually an electric motor, can be reversed readily for reversing vthe direction of rotation of the tap, whereby to eliminate the use of mechanical reversing mechanisms and hence to simplify the construction and render it substantially free'irom adjustments and repairs.

A further object of the invention is the provision of a tapping machine having a reversible driving motor for securing advance and retraction ofthe tap into and` out or the work, and wherein the tapcan be, retracted and re-advanced, by reversal of the motor, at any position of the tap in the work.

A yet further object of the invention is the provision of a tapping machine having a reversible tap-driving motor the direction of rotation of which can be changed at the will of an operative for the purpose of controlling the direction oi' tapping at any depth of the tap in itsvhole.

Another object of the invention is the provision of a tapping machine having a reversible tapdriving motor and a manually operated handle which is operated to advance the tap toward and away from'the work and also to control the direcv,tion of tapping by controlling the direction of rotation of 'the motor.

A further object of the invention is the provision'of an improved tapping machine having a manually operable part movable in one direction to advance the tap toward the work and the rotation of the tap ina feeding-direction and movable in the opposite direction to eiiect the rotation of the tap'ollt ofthe work and the tap away from' the work. e

Another object .of the inventionv is the provision oi a tapping machine having an advanceable and r`etractible'gtap-carrying spindle driven' byia reversible motor, the spindle beingiadvanceable and retractible by vhand and also by the action of the tap in the work due to the direction of rotation of the tap, a switch member movable manu-f' ally andalso by the spindle into motor controlling positions. and a lost motion connection between the switch and the spindle so that ,the switch can be controlled manually movements of the spindle.

A further object of the invention is the provision of a tapping machine having an advanceable and retractible tap carrying spindle driven by a Areversible motor, and means, and particularly manual means, for advancing and rotating the spindle and ,for controlling the direction of rotation of the motor at any depth of the tap in the work.

A yet further object of the invention is generally to improve the construction and operation of tapping machines.

Another object of the invention is an arrangement whereby a motor driven drilling machine can be adapted for tapping purposes at small expense; and also restored for drilling purposes when desired in a simple manner.

during tap-operated Another object of thisy invention is to provide a reversing mechanism for a tapping device which will be very sensitive. A

Other objects oi the invention are to provide a simple and at the same time sensitive means for transmitting the motion of a hand-operated lever in Such a way as to reverse the motor by an electric control and to provide that control in a simple, sensitive and effective form. A

Other objects and advantages of theiinvention will appear hereinafter.

Fig. 1 is a side view of a drill and tapping machine provided with invention.

a preferred form of .our

Fig. 2 is a similar view on enlarged scale with parts cut away to show the sliding head.

Fig'. 3 is a sectional view of theswftch connecting device shown in Fig. 2.

Fig. 4 is a horizontal sectional view on the line 4 4 of Fig. 1. v

Fig. 5 is a front elevation o! a pair of trolley wires shown in Fig.' 4.

Fig. 6 is an end view of the, illler block.

Fig. '7 is a plan of the brush holder.

Fig. 8 is a view similar tojFig. 3 with the parts in a different position.

Fig. 91s an elevation looking in the direction of the arrow il in Fig. 4, and I Fig. -l0 is a diagrammatic wiring diagram showing the connecting vparts in position.

The invention, as shown, is applied to an ordinary drilling machine having a base Il), gooseneck Il and-adjustable work support i2. This interior construction oi' drill, as usual, is provided with a meier la, here shown as a three phase motor, for driving a spinidly mounted on the 'gooseneck. The quill is slidable in the head 3 and is provided with a.

.rack |8 and a chain I1 for connection with a counterbalancing weight which is not shown but is located inside the frame so that the spindle remains in any position into'which it may be left when the tapis out of the hole. Meshing with the rack is a quill-raising and lowering pinion |3- loose on a cross head stud I9. On this stud is ilxed a hub 20 having radial operating arms 2| rotatably-loose in the hub and which constitute the means bywhich the quill is fed by hand.

On the stud I9 is a bushing 2B filling the space between the gear and a collar 29 beyond which is the hub 30 of a switch ringer 3|. Said collarm29 is' fixed to said stud I9 by suitable means andv hence is rotatable with said/stud. Said hub 30 of the switch finger is pressed against the outer face of said collar by a compression spring 45 which at its outer end bears against a nut screwthreaded on the stud I9. The hub 3| of the switch finger and the collar are thus pressed into frictional engagement with each other. Said switch finger is otherwise free for rotation on said stud and hence said stud can rotate independently of corresponding movement of said switch finger when the latter is' held from rotation.

Said switch finger is moveable into and out of operative engagement with the plunger 53 of a Lswitch 52 having separable contacts 54 which, in the particular switch illustrated are normally disengaged but are adapted to be engaged by the depression of the plunger 53 by movement of the switch linge" in a counterclockwise direction, Fig. 10.' When themachine is used for drilling, this switch iinger rests on a cam 32, Figs. 2, 3, and 4, which is xed on a shaft 33 provided with ahandle 34 for operating it. This handle is locatedkoutside the head 6 in which these parts are housed. The handle can be turned to lower thecain so that the switch finger can operate for tapping.'

The slidinghead is fixed in adjusted position for drilling and tappingv by a binding screw 4. The sliding head is provided with a fixed screw 1 having adjustable stop nuts 8 at both ends and passing freely through a hole in a lprojection 9 whiclr is mounted on the quill and constitutes a.- stopping device vfor use in drilling and which isold in the art. Engagement of the stop nuts with the projection limits the uppermost and lowermost positions of the spindle.

The stud i9 is operatively connected to thev pinion 'I8 by means including a latch 22 which is keyed on the operatingarmsI 2| and is pushed. down` into latchin'g psition by a spring 22a bearing against a surface 3 on said stud hub 20 itself. .tends between teeth 25 cut on a collar 20 integral with the pinion IB, so the hub 2|! can be turned to raise and lower the quill. It will be noticed that this projection 24 ofthe latch is considerably narrower than the spaces between theteeth to allow for angular play between the` stud and gear and hence between the spindle and switch as will be explained in greater detaillater.

Carried by a knockout lever 31, embracing the projection 9 and moving with it and with the Iquill, is a hub 38 having a smooth perforation for receiving another screw 39 of -a similar character to the screw 1; and constituting a knockout rod.

This rod has adjustable lock nuts 40 for the same come Arieti by the sliding head 6.

This latch has a projection 244 which ex-' purpose as the nuts l but theA upper nuts are only limiting stops. At its lower end said rod is xed to a bushing 4| which is spring-pressed upwardly by a spring 42. This bushing is arranged to slide' in an opening in a switch enclosingfcasing 21 car- Y In the casing is a plunger 43 which is separated from the knockout rod 39'by a. spring 44 in -the bushing. When the quill moves downwardly until the hub 38 engages the lower nut 40 the knockout rod. willfof course, be forced down and will i'orce down the plunger 43 against the switch ilnger 3|. If released for operation by rotating the holding cam 32 into the position as shown -in Fig. 3. This is not a positive movement but is cushioned by the springs but it turns the switch linger. Said spring 45 surrounds the cross headstud I9 and holds the hub 3|) against the collar 29 to provide friction.

A pin is carried by the casing 21 and is located in a vertically elongated slot in the pin 43 to permit sumcient movement of said pin to effect operation of the switch finger 3| and to prevent unintentional withdrawal of the pin from the casing.

vprovided lwith a brush holder 49. {This brush.

holder carries a pair of brushes 5U which .engage a vpair of trolley wires 5| partially embedded in A the insulating cylinder 46 but havingvan exposed These two trolley wires are insulated surface. from each other and each of the brushes 50 engages one of them. These brushes are individually connected by wires 5 la with the switch 52. The closing of this switch by the depression of said plunger 58,` which is forced down by the switch finger above mentioned, serves to close the swii :h 54 and connect these trolley. wires.

The two /trolley wires 5| are connected with a solenoid 55 according to the diagram of Fig. 10 so that this completes the circuit and the :solenoid is energized. The solenoid circuit is illustrated in Fig.v 10 in a well known way to show the running of the Athree phase motor forward or in reverse, according to the circumstances. The circuit 'arranged is such that when the solenoid is energized, the motor is reversed and when it is de- 'energized the motor will run in a forward direction owing to the descent of the solenoid plunger in this case by the action of gravity.

In the operation of tapping, the operator may let go of the arms 2| after the tap is in the hole, provided the arms of equal length on opposite sides of the axis o'f the stud I9 or the stud otherwise is equally balanced. Itis not intended, however, that the operator shall let go of the arm but rather that he shall exert pressure on the arm to move the spindle in the direction of tapping,

that is, down for tapping into a hole and up for backing out of the hole, as will be explained later. The tap, oi course, will feed itself down at a predetermined rate. The lower nuts 40 are so set that when the hole is nearly tapped the hub 38 down during the rest of the downward feed of the .will engage them. This' pushes the knockout rod tap in the hole and pushes'down the rod 43 to depress the switch finger 3|. This closes the switch and connects up the circuits through the brush holde'x` and the Atrolley wires to the solenoid 55. The result of this is the energization ofthe solenoid and the raising of the plunger 50 and the reversal of the motor, as will be seen clearly in the diagrammaticwiew in Fig. 10.

The tap, by Lthe rev`erse rotation, will begin to thread itself out of the hole and almost linmedi'- ,ately the plunger 43 will rise. However, on acv count of the pressure of the spring 45 against the hub of the switch finger and the friction of the hubl against the collar 29; which is now rotating reversely, the switch finger is held down. Thus the switch remains closed so that the motor will not again change its direction, except under manual control, so long as the tap is in and is screwing 'itself out of the hole. When the tap gets out o f the hole the spindle does not rise further and hence there is nothing to hold down the switch finger, except a possible imbalance of the stud |79 and associated parts, assuming there is no manual upward pressure on the operating arm, and the switch iinger may rise and open the circuit. If

the motor now starts to rotate in'a forward direction, that is immaterial.- Of course, if lthe operator moves the operating arm`2| he can cause the reversal of the motor at any time.

With the construction described the operator has control of the direction of tapping at any part of the hole in Vwhich the tap may be in. For

instance, assume that the tap is out of the hole and that the tap driving motor |3 is reversely rotating because 'the switch inger 3| holds the switch closed and the solenoid energized for any reason. The operator desires to advance the tap into the hole. He thus moves an arm 2| downwardly and hence turns the stud I9 in a'clock-V Wise direction, Fig. 2. The first v result of the movement of the stud is to raise the switch ilnger 3|, thereby effecting the deenerg'ization of the.

solenoid 55 and the quick reversal ofthe directionof the motor to a forward direction. The pinion I8 is not rotated during the operation of the switch .because of the clearance between the latch tooth 24 andthe opposing teeth 250i the pinion hub 26. Further movement of the arm 2| in the same direction causes the latch tooth 24 to engage a tooth 25 and hence rotates the pinion and moves the spindle downwardly. Thus the tap l will screw itself into the hole; and the switch is kept up by following the spindle down with the arm 2|. If, however, the arm 2| is raised to turn the stud in the lopposite direction, this movement being permitted by the clearance between the teeth'24 and-25, the switch finger 3| will be de pressed and effect the closing of the switch contacts 54 so that the motor andthe spindle will be reversed 'in rotation and the tap will back out of the hole. It. will be apparent that the oper--` ator 'thus can control the direction of tapping with the tap anywhere in the hole, it being merely necessary for the operator to rotatethe arm carrying .hub 2li and the stud I9 in one direction to screw the tap into the hole and inthe opposite direction to backthe tap out of the hole.

The angular clearance between the tooth 24 of the latch 22 of the arm-carrying hub 2l .and the opposing teeth 25 of the pinion hub 25 is important and is enough to permit suilicient rotation of the stud I! independently of corresponding rotation of the pinion I8 to eifect movement of the switch finger 3| between switch-open and closed positions. Thus, if, for instance, the spindle is descending due to the tap screwing itselfinto the hole, the stud I9 is free to' be rotated to-move the switch nger 3| downwardly to close the switch contacts 54 and effect the reversal of the motor and tap, If the tap isbacking out of the hole by its backward rotation, the clearance between tooth 24 and the opposing teeth 2l permits the stud Ilto be rotated to open the switch and effect the forward rotation of the tap.

The machine thus can be operated to simulate hand tapping where, for instance, the tap is advanced into the hole by' a succession of short 3. therotary advancing movements with interposed.

backing out movements.

The pressure of the spring 45 on the hub 3D of the switch linger 3|, and hence pressure ,of the ,hub on the collar 29, is suilicient to ensure sure movement ofthe finger in response to rotation of the collar and stud I9, when the rotation is in a direction inwhich the nger is free for movel ment, and yet is light enough so that there is no undue pressure between the linger and the switch 52 on rotation of the stud.

The latch 22 carrying the tooth 24 can be rotated in a clockwise direction, Fig. 9, upon slight rotation of the arms 2| about their axes, whereby to elevate said tooth out of the interdental space between two confronting teeth 25`of the pinion hub 26. ,'I'hus, with the tooth maintained elevated, the arm-hub 2li can be rotated to position the latch tooth to enter'the space between another pair of confronting teeth 25. This arrangement permits the arms 2| to be maintained in a convenient position throughout the range of vertical movement of the spindle.

Having thus described our invention and the advantages thereof, wwe do-not wish to be limited l to the details herein disclosed; otherwise than as set forth in the claims but what we claim is:. l. In a tapping machine, the combination with a reciprocable spindle for supporting a tap and a finger will be operated to closelthe switch.

2. In a tapping machine, the combination with a reciprocable spindle for carrying a tool, a re-v versible motor for rotating the spindle, vand a solenoid connected with the motor, of a pair of wires separated and insulated from each other, a pair of brush fingers, each inl contact with one of said wires, a normally open switch for connectlng said wires, means for connecting said wires with the opposite poles of the solenoid, a rod mounted to be capable of moving vertically, means movable .vertically with the spindle for actuating said rod and means by which the descent of the rod will close the switch, said solenoid being arranged normally to feed power to the motor to rotate it forwardly whenthe solenoid is deenergized and for connecting the motorv to revers it when the solenoid is energized.

'3. 1n a tapping machine, the combination with a reciprocable spindle for carrying a tool, a reversible motor for 'rotating the spindle, and a solenoid connected with the motor, of a pair of 1 wires separated and insulated fromeach other,

of saidwires, means for connecting said wires with the opposite poles of the solenoids, a normally open switch for connecting said wires, a rod mounted to be capable of moving vertically,

means movable vertically with the spindle for 'actuatingsaid rod, a plunger,"cushioning means means forclosing the switch when the knockout for connecting the plunger-with the rod, whereby the descent oi the rod willpush' the plunger down.

and means by which the descent o! thi:J plunger 'will close the switch, said solenoid being' arranged normally to feed power to the motor to Yrotate it forwardly when the solenoid is deenergized and ior connecting-the motor to reverse 'it when, the solenoid is energized.

4. In a tapping machine, the combination with a reciprocable spindle for holding a tapping tool and areversible motor'i'or rotating the spindle,y

of a slidable head, ways -onwhich the head is mounted, said head having a recess, a bushing slidable in the recess, a spring tor holding `the bushing up in the recess, a knockout rod ilxed to said bushing, means whereby, when thespindle descends to a predetermined point the knockout rod will be forced down, an electric switch.

rod is pushed d own, a solenoid for controlling .the

tion of rotation oi' the motor, and means for co ecting the` switch with the solenoid to'energize it and reverse the motor when the switch isclosed.,

5. In 'a tapping machine, the combination with a reciprocable spindle for supporting a tappingl tions from the switch through the brush nngers and the two wires ior reversing the motor when the switch is closed.

6. lIn a tapping machine. the combination with la reciprocable spindle for supporting a tapping -tool and a reversible motorfor rotating the spindle, of 'an insulating member having Is slot, a pairA of conducting wires supported by the insulating member and insulated thereby from each' other, a brush holderhaving a pair oi' brush fingers, each resting against the exposed surface of one of said wires, a' switch nngen'means i'or operating said switch linger -when the spindle descends, an electricswitch nnger, a solenoid 'for controlling the direction oi rotation ofthe motor.

means for connecting said wires with the opposite poles oi the solenoid, and electrical connections from the switch through the brush ngers and the two wires for reversing the motor when the switch Y "1. In a tapping machine, the combination with areciprocable spindle for supporting the tapping tool and 'a reversible motor for rotating the spindle, of a switch nnger, an electric switch-'opthe work.

j, In a tapping erated bythe switch linger, means whereby the switch finger is actuated to close the switch when the spindle descends to a 4certain point. means connected with the switch vtor reversing the mo' `tor, a cross head stud, a collar thereoma spring between the collar and the hub for holding the hub irictionally `with respect to -the cross head stud whereby, when the switch il'nger ls operated 'i to close theswitchto reverse the motor. the friction will hold 'the cross head stud in'switch cios ing positionso long as the tap is being (ed out o! machine, the combinationvwith recpseislespmdie mi supporting the umn:

tool and a-reversible motor torrotating the spindle, of a cross head stud, a quill, means on sans it any 'mm3 range of movement and independentlyof any er1 the stud lor operating 'the quiiLa switch ringer .having a hub 'through which the cross headstud passes, an electric switch operated by the switch nager, means whereby the switch finger is ac-- tuated to close the switchwhen the spindle d e- 5 scends to a certainjpoint, means connected with the switch for reversing the motor, a collar on the cross headstud, a spring between the collar and the hub for holding the hub frictionally with respect to the cross head stud, whereby, when the -l switch ringer is operated to closethe switch to reverse the motor, the friction will hold thecross head stud in switch closing position so long as' the tap is being fed out of the work.

9. In a tapping machine,the combination with l a reciprocable spindle ior carrying the tapping toolandk a reversible motor for rotating the spindle, of a switch linger, an 'electrie switch adapted to be closed by the motion oi' the switch linger, a knockout rod, means carried bythe spindle ronmo'ving'the Iknockout rodt'o actuate the finger to close'tl'ie switch, a solenoid for controlling the direction of rotation of the motor, means connected with said switch for energizing the solenoid when the switch isclosed, and means 2 5 for' lifting the finger out of operative position to-render the machine operable for other work.

10. In a tapping machine,'the combination with a reciprocable spindle lor/ supporting the tapping tool and a'reversible motor'ior rotating 30 the spindle, o! a cross head'stud, a quill surp rounding the spindle, means loose on the cross l head stud for raising and lowering the quill.

a toothed collar nxed to said means, -a hub fixed on the .cross head stud, o'peratingarms on thehub, a latch carried on'the operatingarms ad movable in the huh and having a latch tooth entering the spaces between the teeth on the collar and o! a width less than those spaces, for o member for advancing and retracting said spindle and for changing the directionoi tapping repeatedly during the progress ofthe tapping operation. y

12. In a tapping machine, the combination of a tap-drivingspindle, a reversible spindle-driving motor, an operating member for reciprocating said spindle, and vmeans operatedby said operating member for advancing vand retracting said. spindle and for reversing said the direction oi tapping repeatedly throughout' the range of movement of said spindle. v

-13. In a tapping machine, the combination oi an' advanceable and rectraotible tap-driving spinspindle, a spindle-driving motor, and means operated by said operating member for changing\ direction ot movement or said 'spindle and separately iorchanging the direction o! tapping' oi said spindle throughout its 6 gagement between the tap 'and the work.

14; In a Itapping machine, the combination of `a tap-'drivingl spindle, a reversible spindle-driving motor. means lor advancing and'retractins 70- .f said spindle, andmotor controlling means having an operative connection with and operative in response toa change in the' direction oi move.

ment oi satdy'spindle'advandn'g and retracting motor independ ently of movement or said spindlefor changing 4die, an operating member for reciprocating said 50 imlaans vfor changing thsdireetionof rotation ofy 75 said spindle at any'position thereof between i limits of movements.

15. In a tapping machine, the combination of a tap-driving spindle, a reversible spindle-driving motor,-means for advancing and retracting said sindle, an operating member therefor, and motor reversing means operated by said member for changing the direction of rotation of said motor at any position oil-said spindle between lts limits of movement.

16. In a tapping machine, the combination of a tap, a reversible motor for reversely rotating said tap, means for advancing and retracting said tap, an operating handle for said means. and means responsive to reversal of movement oi said handle for changing the direction vof rotation yof said tap.

17. In a tapping machine, the combination o! a tap-driving spindle, a reversible spindle-driving motor,and means for starting the advancing of said spindle and about concurrently therewith changing the direction of rotation of said motor and for startingJthe retracting of said spindle and about concurrently therewith changing the direction of rotation oi said motor.

18. In a tapping machine, the combination of a tap-driving spindle, a reversible spindle-driving motor, advancing and retracting means for said spindle, motor controlling means for controlling the direction of rotation of said motor, and common operating means for both aforesaid means operative in one direction to effect the advance of Said spindle and about concurrently therewith one direction of rotation oi' said motor and operative in the opposite direction to eiect the' retraction of said spindleand about concurrently therewith'the opposite direction of rotation of said motor.

19. In a tapping machine, the combination of Y a tap-driving spindle, a reversible spindle-driving motor, advancing andv retracting meansv for said spindle, motor controlling'means for controlling the direction of rotation of said motor, and common operating means for both aforesaid means operative in one direction to eil'ect the advance of said spindle and one direction of rotation of saidr motor and operative in the opposite direction to secure the retraction of said spindle and the opposite direction of rotation of said motor, said operating means having a lost-motion connection with one of said two Vaforesaid means operative to secure reversal of said motor in adv vance of reversal of movement of saidspindle.-

420. In a tapping machine, the combination of a tap-driving spindle, a reversible spindle-driving motor, advancingand retracting means'for said spindle, motor controlling means for controlling the direction of rotationof said motor, and com- 's mon operating means for both aforesaid means operative to effect the operation oi said-motor controlling means prior to operating the spindle.

21. In a tapping-machine, the combination oi a tap-driving spindle, a reversible-spindle driving motor, a control device movable in opposite directions to effect the advance and retraction of said' spindle and motor Icontrolling means responsive to a change in the direction oi' movement of said device at any position of the tap in the work to eiect the reverse rotation of said motor.

22. Ina tapping machine, the combination of a tap-driving spindle, a reversible driving motor, a control device vmovable with said spindle' for advancin'g and retracting it, motor controlling -means fesponsive'to a reversal of movement o! Y said control device to elect the reversal o! said in opposite directions, a rotatable stud for ro- 75 motor, and means to effect' the operation of said motor controlling means prior to movement oi.' said spindle.

-23. In a tapping machine, the combination of a tap-driving spindle, a reversible spindle-driving motor, manual means rotatable with movements of said spindle ior advancing and @etractlng it, and switch means for controlling the direction of rotation of said motor having an operative connection with said manual means and operated by movements thereof in oppositedirections for effecting the reverse rotations of said motor, said manual means having a loose engagement with said spindle and said motor controlling means having a connection with said manual means for concurrent movement therewith at least to an extent sufficient to' eiect the operation of said directions, and means conditioning said switchmeans for 'operation in response to a reversal of movement of said Icontrol member to eect reversal of said motor. f

25. Ina tappingmachine, the combination of a tap-driving spindle, a reversible spindle-driving motor, means movable in opposite directions for effecting advance and retraction of said spindle, switch means for eilecting reverse rotations of said motor, operating means for said switch means movable into?l different positions correvsponding to reverse rotations of saidmotor, and

a yieldable driving connection between said spindle advancing and retracting means and said switch operating means operative to secure movex ment of said switch operating means in opposite directions about concurrently with opposite movements of said spindle advancing and retracting means and further movement oi' said latter y means independently of' said switch operating means.

26. In a tapping machine, theA combination of an advanceable and retractible tap-driving spindle, a reversible spindle-driving motor, a member rotatable in opposite directions for reversely moving said spindle, switch means movable in opposite directions for eil'ecting reverse rotation of said motor, and means providing a slipable driving connection between said rotatable member and said switch means.

2'1. ma tapping machine, the combination of' an advanceable and retractible tap-driving Aspindie, a reversible spindle-driving motor, a member rotatable in opposite directions for reversely moving said spindle, switch means movable in opposite directions for e'iecting reverse rotations of said motor, means providing a slipabletdriving connection between said rotatable member and said means, and means providing for the operag tion of id switch means independently oi said spindle.

28.` In a tapping machine, the combination oi.

an axially movable tap-driving spindle, a reversible spindle-driving motor, means including a rack and pinion for' moving said spindle axially means for effecting reverse rotations oi said motor, operating means for said switch means having a yielding irictional driving connection with said stud, and means for limiting movemento! said operating means in opposite' directions.

29. In a tapping machine, the combination o! an axially movable tap-driving spindle, a reversible spindle-driving motor, means including a rack and pinion for moving said spindle axially in opposite directions, a rotatable' stud for rotating said pinion in opposite directions, switch means lor eecting reverse rotations oi said'motor, operating means for said switchmeans having a.

yielding irictional driving connection with said stud, means for limiting movement oi said operating means in opposite directions, and means including a loose connection between said stud ',erating meansfor said switch means having a yielding irictional driving connection with said.

stud, means ior limiting movement oi said operating means in opposite directions, and means for varying the angular relation between said stud and pinion.

3l. In a tapping machine, vthe combination of an axially movable tap-driving spindle, a reversible spindle-driving motor, means including a rack and pinion for moving said spindle axially in opposite directions, a rotatable studI for rotating said pinion in opposite directions, switch means ior eiecting reverse rotations of said motor, op erating means for said switch means 'having a` yielding frictional driving connection with said stud, means for limiting movement of said operating means in opposite directions, and means for varying the angular relation between ,said

stud and pinion including a series o! angularlyspaced teeth in driving connection with said pinion, and a latch in driving connection with said stud shittable into position between selected different pairs oi teeth.

32. In 'a vtapping machine,'the combination ci an axially movable tap-driving spindle, a reversible spindle-driving motor, means including a rack and pinion for moving said spindle axially, a pinion rotating stud. motor reversing means operated by rotation of said stud, and a loose driving vconnection between said stud and pinion for eiecting operation of said reversingmeans independently oi rotation o! said pinion.

33.`In a drilling, and tapping machine, the

combination of an axially movable tapand drill driving spindle, a reversible spindle-driving motor, switch means `for etl'ectingreverse rotations of saidmotor, operating means for moving said spindle axially in opposite directions and lor. in-

' -dependently operating said switch means f or securing reverse rotations oi said motor, and means for holding said switch, means from -operation under urge of said operating means for eiiecting axial movement oi said spindle in opposite directions without reversing said motor.

34. In a tappingrnachine, the combination of an axially movable tap-driving spindle, a reversible spindle-driving motor, for moving said o I 20,579 tating said pinion in opposite directions, switch spindle in opposite directions',

. means for securing reverse rotations o! said motor movable into different positions corresponding to opposite directions of rotationoi said motor, and operating meansv i'or'both said spindle movingmeans and saidswitch means, said operating means having a loose connection with said spindle moving means for etiecting operation oi said switch means independently oi movement of said spindle.

35. In a tapping machine, the combination of an axially movable tap-driving spindle,- a reversible spindle-driving motor, means for moving said spindle vaxially V:ln opposite directions, switch means for securing reversefrotations of said mo' tor movable into diil'erent positions corresponding to .opposite'directlons of rotation of said mo tor, and operating means for both said spindle moving means and saidswitch means, said operating means having a loose connection with said spindle moving means for effecting operation of said switch means independently of movement of said spindle, and said switch means having a yieldable operating engagement with said ope'rating means'to permit movement of said spindle independently of said switch means.

36. In a tapping machine, the combination with a reciprocable spindle for supporting the.

tapping tool and a reversiblev motor vfor rot'ating the spindle, of a cross head stud, a quill surfroundingfthe spindle, means loose onthe crossv head stud i'or raising and lowering the quill, a

toothed collar fixed to said means, a hub iixed to said hub having a latch tooth entering the spaces between the teeth on the collar and of a width less Athe cross' head stud, operatingwrms on the hub,

than those spaces, and motor-controlling switch vers/ed until the tap moves out o! the hole in the.

work, said means comprising a member mov-v able `in opposite directions with said spindle, and

, means having an operative connection with saidi stud and arranged to be operated by rotation ot motor-controlling switch means 'movable in one direction to secure forward rotation of said motor and the advance of said spindle by the tap and movable in the opposite direction lto secure reverse rotation of said motor and the retraction' of' said spindle by the tap, and means providing -a slipping frictional driving connection between said switch means and said member, whereby movement of said spindle is eiective in holding said `switch means in the position of the direction move-jV v oi' rotationot the motor that causes such ment of said spindle.

38. In .a tapping machine, a reciprocable tap' for driving the spindle in opposite directions, a

l ca r'rying'and driving spindle, a reversible motor switch for reversing the motor, means including an operating handle' for advancing and retracting the spindle, and connections between the handle and switch and handle and motor roi-'reversing the motor switch at any time during the tapping operation by reversing the' direction .ofmovieitl of the handle.,

39. In a tapping machine.. a reciprocable tapA lcarrying end driving spindle. s reversible motor continued movement of the hsndle in the seme' tor driving the spindle, an loperating handle having a. lost motion drivingconnection with the spindle for advancing and relax-acting it. a moto reversing switch having a connection with sail handle such that the initial movement oi' the handle eilects an operation ot the switch and direction is permitted without a switch operation. said lost motion connection being sumcient to permit switch operation prior to eiective engage-` 

